Blueair 650E Digital HEPASilent Air Purifier Designed for large living rooms, basements, and open workspaces up to 698 square feet in size Patented HEPASilent technology captures 99.97% of harmful particles down to 0.1 microns in size World's highest Clean Air Delivery Rate (CADR) of 450 cubic feet per minute, 5 air changes per hour SurroundAirTM technology takes in air through an area six times larger than the average air purifier E-Series features AUTO setting, automatically adjusting speed according to indoor air quality